McHenry County, IL Building Safety: Plumbing Permits (2026)

McHenry County does not write its own plumbing code: unincorporated territory operates entirely under the Illinois State Plumbing Code, 77 Ill. Adm. Code §§ 890 et seq., which the County Board adopted by reference "without addition, modification, exception or amendment" (§ 15.24.010). Many county code chapters carry local tweaks; plumbing does not, so contractors working outside city limits pull permits against the state text exactly as written, not a McHenry-specific variant. Where any other adopted county code, including the local International Building Code amendments, conflicts with the state plumbing rules, § 15.24.020 makes the Illinois Plumbing Code the controlling authority.

The link to the building permit process runs through the county's amended IBC 101.4.3, which assigns "installation, alteration, repair and replacement of plumbing systems, including equipment, appliances, fixtures, fittings and appurtenances, and where connected to a water or sewage system and all aspects of a medical gas system" to the plumbing code, while routing private sewage disposal and private wells to the separate Public Health Ordinance. In practice, the Department of Planning and Development takes the permit application on its own form (§ 15.04.010, IBC 105.3), and once issued a permit is good for two years but becomes invalid if work is not started within 180 days or is suspended for 180 days; the building official is authorized to grant written extensions of up to 180 days at a time for justified cause (IBC 105.5).